The FSB is pretty much the FSB. However, for your CPU, as long as your motherboard's BIOS can identify the CPU (there are cool identifiers within the CPU that tell the BIOS what CPU it is), the FSB will be automatically configured to your CPU.

Overclocking is when you increase the FSB a bit. Or more than a bit. You can also, and this is what I think you are talking about, set your CPU FSB higher than your RAM FSB. This is what is called an asynchronous FSB.

My personal opinion: Don't mess with Async. It often makes your computer run slower rather than faster.

If you buy a CPU that's front side bus is higher than your Chipsets supported FSB, then your CPU will either not operate, or will automatically be reduced in speed signifigantly to match the chipsets FSB (Assuming we're talking about one socket).

In the case of the Athlon64's, it doesn't really matter. As long as your board supports the core, the FSB (Which is actually the HT link) doesn't get involved.

I have discovered that all human evils come from this, man's inability to sit still in a room. ~Blaise Pascal

Yeah..that's it....I noticed that some Socket 939(AMD64) mobo's support 2000Mhz FSB and some support only up to 800Mhz....so note to self ...when matching mobo to cpu...make sure FSB's match up. Are there any other detailed CRITICAL Matchups between the CPU and mobo I should look into???